Re: PCcard (2)

g.baltissen_at_hccnet.nl
Date: 2001-04-12 12:52:14

Hallo jbevren,

If I may ask, what is your real name?

> > Unfortunally I need 256 bytes for the window PLUS some bytes for I/O. An
> > other solution is decrease the window to 128 bytes but I realy dislike 
> that.
> 
> I dont know of ANY I/O boards that use more than 32 bytes actually.  I'd 
> feel rather comfy iwht 128 bytes if we have dma-to-c64 in the future.

Then I have news for you: If you want DMA, you need that minimum 256 byte 
window. As I already said, I intend to use the 8237. It drives A0..7 
directly, A8..15 is driven thru a latch. Driving A7 thru a latch as well 
only complicates things.

> Grow up.  Throw the FC3 out the window like I did. ;)

I hardly use it but being a techie I opened it and noticed this behaviour. 
And as a techie I dislike this solution. It had been much more nicer to use 
an extra decoder so one could combine this cart with others.

> This is, again, an internal mod ;)

You cannot blame me using a hack because others messed up first. Even 
Commodore is to blame because the REU needs less then 16 bytes but due to 
mirroring, no one else can use (a part of) the other 240 bytes :(

> I'd rather collaborate and make a design the two of us can agree on
> ...
> If we can stay outside, and work from the cart port, we can get much more 
> support from the scene.

As already mentioned, my design will use the the I/O-lines in the first 
place. And you may tell me what IO-line to use for what part :) 
The connection is made using two jumpers. If one intends to use other base 
addresses, (s)he only needs to connect these pins to the outputs of the 
used decoders. 
Until now all my software is freeware, including the sources. This enables 
one to compile its own version. 

But if someone decides to write non-public SW for the standard IO-lines, 
then the above person simply has bad luck :(

How does this sound to you?

> the CIA is at dc00 and dd00.  D700? look at the top of the file. ;)

I understand you would agree on $D7xx as well. Then this could be my 256 
byte window. Then I need another 8 bytes for the I/O. Use an extra decoder 
with one of the CIA's et voila, I have my extra bytes.

Then I have a question: is there a list where you can see which I/O-cart 
use which address?
And then for the SCPU-users: what I/O-addresses does the SCPU use 
(including possible mirroring)? 

Groetjes, Ruud

http://Ruud.C64.org/



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